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As an important application of virtual geographic environments (VGEs), virtual disaster scenes are essential in enhancing the public's risk awareness. However, existing virtual disaster scene visualization methods lack expert guidance and fail to meet the public's requirements, resulting in an ineffective public understanding. Therefore, this paper proposes a knowledge-guided disaster scene 3D visualization framework. First, the public's demand for disaster scene visualization is analyzed, and a geographic knowledge graph of disaster scenes is constructed. Second, through the guidance of the knowledge graph, the virtual disaster scenes are fusion modeled and suitability represented. Third, a diverse organization and adaptive scheduling method of disaster scene data for multi-computing devices is established. Finally, we developed a prototype system for disaster scene visualization, selected a typical disaster, and conducted cognitive experiments with eye-tracking technology. The results show that the proposed method can effectively support the adaptive visualization of virtual disaster scenes for four computing devices and maintain an efficient frame rate. In addition, compared with other disaster scene visualization methods, our framework incorporates semantic knowledge of scene, user, demand, and space. It can effectively convey disaster information and help the public cognize disaster risks and has significant advantages in modeling standardization, personalization, and adaptability. [ABSTRACT FROM AUTHOR]

The visual perception of augmented reality (AR) geovisualization is significantly different from traditional controllable 2D and 3D visualization. In this study, we extended the rendering styles of color variables to include natural material color (NMC) and illuminating material color (IMC) and extended the size to include linear size (LS) and angular size (AS). Outdoor AR geovisualization user experiments were conducted, examining the guidance characteristics of five static variables (NMC, IMC, shape, AS, LS) and two dynamic variables (vibration, flicker). The results showed that the two dynamic variables provided the highest guidance, and among all the static variables, the order of guidance was shape, IMC, AS, NMC, and finally LS. This is a new finding that is different from the color, size, and shape guidance order in 2D visualization and the color, shape, and size order in 3D visualization. The results could be utilized to guide the selection of visual variables for symbol design in AR geovisualization. [ABSTRACT FROM AUTHOR]

The rapid acquisition of deposit volume information and dynamic modeling, as well as the visualization of disaster scenes, have great significance for the sharing of landslide information and the management of emergency rescue. However, existing methods have shortcomings, such as a long and costly deposit volume acquisition cycle, lack of knowledge and guidance, complex operations for scene modeling expression, and low scene rendering efficiency. Therefore, this paper focuses on the study of a three-dimensional visualization and optimization method for landslide disaster scenes guided by knowledge, and discusses key technologies such as the rapid acquisition of landslide deposit volume information based on three-dimensional reconstruction, the knowledge-guided dynamic modeling visualization of disaster scenes, and scene optimization considering visual significance. The prototype systems are developed and used in a case experiment and analysis. The experimental results show that the proposed method can quickly obtain the deposit volume, and the results are equivalent to ContextCapture, Metashape, and Pix4Dmapper software. The method realizes the dynamic visualization of the whole disaster process, provides rich information, achieves high readability, and improves the efficiency of scene rendering, with a stable average rendering frame rate of more than 80 frames/second. [ABSTRACT FROM AUTHOR]

Global change refers to changes in the relationship between humans and nature. It is desirable to actively integrate human social activities into the unified framework of global change so that their mutual relations and functional mechanisms can be understood. This complicated issue necessitates an appropriate method allowing domain experts to collaboratively contribute their knowledge to geoscientific research. Also, an efficient approach to optimize experimentation is of great importance. The reproducibility of research methods and results needs to be improved to boost the sharing of geographic knowledge and resources. This paper proposes a versioned geoscientific workflow and characterizes its full lifecycle using Virtual Geographic Environments, intending to facilitate and improve research related to the interactions between global change and human activities. The geoscientific workflow management is realized using the concept of version management, making geographic simulation methods and computational results easily reproducible and extendable. The sharing and reuse of geographic knowledge in various forms are archived through version management of geoscientific workflows. A versatile prototype system is implemented which enables the visual modeling of geoscientific workflows, the interactive optimization and collaborative evaluation of geoscientific workflows at runtime, the multi-dimensional dynamic visualization of geo-workflow outputs, and role-based access control for data security. [ABSTRACT FROM AUTHOR]

Flood visualization is an effective and intuitive tool for representing flood information from abstract spatiotemporal data. With the growing demand for flood disaster visualizations and mitigation, augmented flood visualizations that support decision makers' perspectives are needed, which can be enhanced by emerging augmented reality (AR) and 3D printing technologies. This paper proposes an innovative flood AR visualization method based on a 3D-printed terrain model and investigates essential techniques, such as the suitable size calculation of the terrain models, the adaptive processing of flood data, and hybridizing virtual flood and terrain models. A prototype experimental system (PES) based on the proposed method and a comparison experimental system (CES) based on a virtual terrain are developed to conduct comparative experiments, which combine the system performance and questionnaire method to evaluate the efficiency and usability of the proposed method. The statistical results indicate that the method is useful for assisting participants in understanding the flood hazard and providing a more intuitive and realistic visual experience compared with that of the traditional AR flood visualization method. The frame rate is stable at 60 frames per second (FPS), which means that the proposed method is more efficient than the traditional AR flood visualization method. [ABSTRACT FROM AUTHOR]

Featured Application: Methods of analyzing user behavior in virtual environments, such as spatial movement and interaction patterns in individuals or within groups, user interface usage. Human performance and navigation activity in virtual environments can be measured and assessed with the aim to draw specific conclusions about human cognition. This paper presents an original virtual geographic environment (VGE) designed and used for this purpose. The presented research is rooted in an interdisciplinary approach combining knowledge and principles from the fields of psychology, cartography, and information technologies. The VGE was embedded with user logging functionality to provide a basis from which conclusions about human cognitive processes in a VGE could be drawn. The scope of this solution is introduced, described, and discussed under a behavioral measurement framework. An exploratory research design was adopted to demonstrate the environment's utility in proof-of-concept user testing. Twenty participants were observed in interactive, semi-interactive and non-interactive tasks, their performance and individual differences were analyzed. The behavioral measurements were supplemented by Object-Spatial Imagery and a Verbal Questionnaire to determine the participants' cognitive styles. In this sample, significant differences in exploration strategies between men and women were detected. Differences between experienced and non-experienced users were also found in their ability to identify spatial relations in virtual scenes. Finally, areas for future research areas and development were pinpointed. [ABSTRACT FROM AUTHOR]

Virtual geographic environments related to dynamic processes contribute to a human understanding of the real world. The results of growth simulations provide good estimations of the future status of forests, but they are typically expressed in plain text summaries, tables or static displays, making it difficult to analyse, understand and further apply the forecast data. The objectives of this study were to propose a strategy for integrating a three-dimensional (3D) geographic environment with growth models and to develop a 3D stand visualization software prototype. Forest growth increments were predicted using the growth models, whereas stand dynamics were simulated using detailed tree models to recognize the changes in the branch whorls and height of individual trees. The spatial structure of the stand was represented by linking each tree diameter class to a spatial distribution according to the features of a Voronoi diagram. The stand visualization system VisForest, which allows users to predict increments in the diameter and height of trees, was extended to estimate the number of trees in each diameter class and to visualize many aspects of a forest stand, e.g., individual tree structure, stem diameter at breast height (DBH, i.e., 1.3 m) distribution and height. The software system provides a specialized, intuitive tool for the visualization of a stand, thus facilitating the participation of various stakeholders in management and education. [ABSTRACT FROM AUTHOR]

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This paper presents the results of a research aiming natural and technological hazard, and risk assessment and mapping in Web-based holistic geographic environment, and the implementation of the Sendai Framework for Disaster Risk Reduction 2015-2030 in Armenia. A common spatial multi-criteria evaluation method was used for natural and technological hazard, risk and population vulnerability assessments. The virtual geographic environment developed by the authors during the previous period of investigations was upgraded and used for the implementation of this research. It involves the following components: 1. geodatabase, 2. modeling and simulation, 3. interface for digital mapping, 4. metadata, 5. Web-based network service for collaboration. Moreover, the country specific natural and technological hazard, risk and population vulnerability assessment methods were developed, implemented, and appropriate digital maps were created. [ABSTRACT FROM AUTHOR]

In this paper, we address two challenging issues underlying spatial simulation using software agents immersed in virtual geographic environments (VGE). First, the way to describe virtual VGE models using accurate spatial decomposition approaches structured using graph theory techniques. Second, the use of graph abstraction techniques to support realistic and advanced navigation and path planning capabilities for software agents considering the VGE's characteristics. In order to illustrate our contributions to the growing field of spatial simulations, we present and discuss a case study involving an urban VGE model populated with agents who autonomously and differently interact with multiple abstractions of the same physical environment. [ABSTRACT FROM AUTHOR]

Due to their strong immersion and real-time interactivity, helmet-mounted virtual reality (VR) devices are becoming increasingly popular. Based on these devices, an immersive virtual geographic environment (VGE) provides a promising method for research into crowd behavior in an emergency. However, the current cheaper helmet-mounted VR devices are not popular enough, and will continue to coexist with personal computer (PC)-based systems for a long time. Therefore, a heterogeneous distributed virtual geographic environment (HDVGE) could be a feasible solution to the heterogeneous problems caused by various types of clients, and support the implementation of spatiotemporal crowd behavior experiments with large numbers of concurrent participants. In this study, we developed an HDVGE framework, and put forward a set of design principles to define the similarities between the real world and the VGE. We discussed the HDVGE architecture, and proposed an abstract interaction layer, a protocol-based interaction algorithm, and an adjusted dead reckoning algorithm to solve the heterogeneous distributed problems. We then implemented an HDVGE prototype system focusing on subway fire evacuation experiments. Two types of clients are considered in the system: PC, and all-in-one VR. Finally, we evaluated the performances of the prototype system and the key algorithms. The results showed that in a low-latency local area network (LAN) environment, the prototype system can smoothly support 90 concurrent users consisting of PC and all-in-one VR clients. HDVGE provides a feasible solution for studying not only spatiotemporal crowd behaviors in normal conditions, but also evacuation behaviors in emergency conditions such as fires and earthquakes. HDVGE could also serve as a new means of obtaining observational data about individual and group behavior in support of human geography research. [ABSTRACT FROM AUTHOR]

Virtual geographic environments (VGEs) have been regarded as an important new means of simulating, analyzing, and understanding complex geological processes. Plants and light are major components of the geographic environment. Light is a critical factor that affects ecological systems. In this study, we focused on simulating light transmission and distribution within a three-dimensional plant canopy model. A progressive refinement radiosity algorithm was applied to simulate the transmission and distribution of solar light within a detailed, three-dimensional (3D) loquat (Eriobotrya japonica Lindl.) canopy model. The canopy was described in three dimensions, and each organ surface was represented by a set of triangular facets. The form factors in radiosity were calculated using a hemi-cube algorithm. We developed a module for simulating the instantaneous light distribution within a virtual canopy, which was integrated into ParaTree. We simulated the distribution of photosynthetically active radiation (PAR) within a loquat canopy, and calculated the total PAR intercepted at the whole canopy scale, as well as the mean PAR interception per unit leaf area. The ParaTree-integrated radiosity model simulates the uncollided propagation of direct solar and diffuse sky light and the light-scattering effect of foliage. The PAR captured by the whole canopy based on the radiosity is approximately 9.4% greater than that obtained using ray tracing and TURTLE methods. The latter methods do not account for the scattering among leaves in the canopy in the study, and therefore, the difference might be due to the contribution of light scattering in the foliage. The simulation result is close to Myneni's findings, in which the light scattering within a canopy is less than 10% of the incident PAR. Our method can be employed for visualizing and analyzing the spatial distribution of light within a canopy, and for estimating the PAR interception at the organ and canopy levels. It is useful for designing plant canopy architecture (e.g., fruit trees and plants in urban greening) and planting planning. [ABSTRACT FROM AUTHOR]

Emergency risk assessment of debris flows in residential areas is of great significance for disaster prevention and reduction, but the assessment has disadvantages, such as a low numerical simulation efficiency and poor capabilities of risk assessment and geographic knowledge sharing. Thus, this paper focuses on the construction of a VGE (virtual geographic environment) system that provides an efficient tool to support the rapid risk analysis of debris flow disasters. The numerical simulation, risk analysis, and 3D (three-dimensional) dynamic visualization of debris flow disasters were tightly integrated into the VGE system. Key technologies, including quantitative risk assessment, multiscale parallel optimization, and visual representation of disaster information, were discussed in detail. The Qipan gully inWenchuan County, Sichuan Province, China, was selected as the case area, and a prototype system was developed. According to the multiscale parallel optimization experiments, a suitable scale was chosen for the numerical simulation of debris flow disasters. The computational efficiency of one simulation step was 5 ms (milliseconds), and the rendering efficiency was approximately 40 fps (frames per second). Information about the risk area, risk population, and risk roads under different conditions can be quickly obtained. The experimental results show that our approach can support real-time interactive analyses and can be used to share and publish geographic knowledge. [ABSTRACT FROM AUTHOR]

Building fire is a risky activity that can lead to disaster and massive destruction. The management and disposal of building fire has always attracted much interest from researchers. Integrated Virtual Geographic Environment (VGE) is a good choice for building fire safety management and emergency decisions, in which a more real and rich fire process can be computed and obtained dynamically, and the results of fire simulations and analyses can be much more accurate as well. To modelling building fire scene with VGE, the application requirements and modelling objective of building fire scene were analysed in this paper. Then, the four core elements of modelling building fire scene (the building space environment, the fire event, the indoor Fire Extinguishing System (FES) and the indoor crowd) were implemented, and the relationship between the elements was discussed also. Finally, with the theory and framework of VGE, the technology of building fire scene system with VGE was designed within the data environment, the model environment, the expression environment, and the collaborative environment as well. The functions and key techniques in each environment are also analysed, which may provide a reference for further development and other research on VGE. [ABSTRACT FROM AUTHOR]

Virtual geographic environment (VGE) aims to express the real-world naturally, and support the complex geographic analysis. The data environment, fundamental of VGE, is expected to support the data management, analysis, sharing and application requirements of the massive complex geographic spatio-temporal data. In this paper, we summarized the key problems in the construction of the data environment of VGE. The unified spatio-temporal data model and a new data structure were developed according to the geographic rules. The organization and compress storage mechanism of massive spatio-temporal data were also developed. With these foundations, case studies, which integrate the global, regional and city scale data to operate complex data modeling and analysis, are performed. The results showed that the construction of the integrated data environment of VGE can largely improve the efficiency of GIS analysis, which also provides a potential new tool to support the complex geographic analysis. [ABSTRACT FROM AUTHOR]

Due to advances in rendering techniques and hardware capability, stereoscopic 3D (s3D) visualization is becoming increasingly common in daily life. However, this does not change the fact that stereo effects and visual comfort depend greatly on how the related parameters are controlled during the production of the s3D images. In geo-virtual reality systems, which are important browsers for Digital Earth, the maintenance of these parameters is deeply related to the navigation process. Therefore, the navigation method in such systems requires special care. This paper presents a new flying method based on aCubemapstructure. The method defines aVehiclemodel and modifies the originalCubemapstructure by adding a front view camera during the navigation; it allows the users to fly through a virtual geographic environment with automatic speed control, smooth collision resolution, and dynamic adjustment of the s3D-related parameters. A user test was conducted to compare this new method with the original method based on theCubemapstructure. The results show that the new method performs better than the former one for it provides a convenient interaction experience with improved stereoscopic effect, and diminishes visual discomfort. [ABSTRACT FROM PUBLISHER]

As a next generation geographic analysis tool, Virtual Geographic Environments (VGEs) have remarkable predominance in enhancing human cognition of tine geographic world and in solving geographic problems. Most studies currently focused on VGE structures and technologies. However, research productions on basic theory, such as geographic semantics and data representation models, are few. In particular, the weakness of VGE cognitive theory has restrained the further development of VGEs. VGE cognition attempts to improve the usability, efficiency, equity, and profitability of VGEs with geo-knowledge obtained through the synthesized research of human geographic cognition rules, as well as the VGE nature and building methods. This research provides not only an efective guide to VGE construction but also theoretical and methodological guidance to the geographic cognition, geographic analysis, and modeling of remote sensing information. This article reviews several understandings of VGEs and suggests that cognition research on VGEs should be derived from the perspective of system theory to contribute to the future scientific development of VGEs. From this perspective, VGEs are complex systems of human environments, virtual environments created by computers, and realistic environments. The differences between the cognition of VGEs and other similar concepts are discussed to draw their clear boundaries. Geographic and map cognition are important bases of VGE cognition, but developing a new cognitive research framework of VGEs in reference to VGE characteristics are necessary. Thus, a cognitive research framework is developed from similarities that include thinking, perception, geometry, characteristic, and discreteness similarities in both realistic and virtual environments. Thinking similarity is the emphasis and the difficulty of VGE cognitive research. It is also the basis of building VGEs that are consistent with human cognition. The course of human cognition is through image schema, category, conception, and meaning. Thus, thinking similarity should include the specialization of human cognition models on geographic environments, context model building of VGEs, computer model of geographic concepts, and formalization and contextualized representation of geographic models. Perception similarity is an important factor in generating immersion and is a key to distinguishing VGEs and other spatial cognition tools. Thus, the multi-modal interaction, dynamic representation adaptability, cognitive load, and work efficiency experimentation of VGEs should be studied. VGEs should balance realistic representation and non-realistic representation, which is called realistic representation adaptability to geometry similarity. Given the multi-scale characteristic and scale dependence of both the geographic process and study method, characteristic similarity should include multiple-scale adaptability and representation of formalization models. VGE uncertainty is produced when discrete geographic data are translated into a continuous spatialtime process representation, which is lacking in VGE research. Based on the above framework, VGE cognitive research is placed in its wider context. The function of tine geographic experiment platform of VGEs and human function in VGEs is also emphasized. This study has a large significance in deepening VGE research. [ABSTRACT FROM AUTHOR]

The article elicits the theme by the analysis of the geographic experiment teaching status, to construct the virtually experiment system simulating geographic environment. It discusses the function of the system in solving the conflict of educational scale and quality and in overcoming the imbalance problem of experiment resource and improving of student creativity, and puts forward a way to construct the typical application cases. From the point of experiment teaching, the virtual geographic environment experiment system aims at the training of operating ability, practical ability and creativity, integrates the experiment teaching resource, extends the teaching method, urges the student comprehensive development in experimental operating ability, field investigation ability, synthetic analysis and application ability etc. It can also foster the high quality personnel to enrich their pioneer spirit, creativity ability and international competitiveness, The investigation promotes the reform of geographic experiment teaching to meet the society requirement. [ABSTRACT FROM AUTHOR]

This paper presents a reality-virtual fusional campus environment. It is an online 3D platform with some aspects of real information merged together. The whole platform is based on OpenSimulator with detailed geo-models to represent the university campus. Some preliminary experiments were done to integrate the realistic information with the virtual campus for making the geo-environment not only with detailed indoor and outdoor models, but also with the real representations of the physical world. The overall motivation is to provide a framework with strong support for reality-virtuality fusional modeling in a collaborative 3D online platform for research purposes. [ABSTRACT FROM AUTHOR]

On the basis of previous work, this paper designs an intelligent agent based on virtual geographic environment (VGE) system that is characterized by huge data, rapid computation, multi-user, multi-thread and intelligence and issues challenges to traditional GIS models and algorithms. The new advances in software and hardware technology lay a reliable basis for system design, development and application. [ABSTRACT FROM AUTHOR]

In general, the article deals with the possibility of connecting spatial information from the fields of architecture and geoinformatics. BIM is a commonly used digital representation of physical and functional characteristics of a building and its components throughout the building's whole life cycle with the focus on large-scale details that finds its application in the fields of architecture, civil engineering, and construction or project management (Gu, London, 2010; Volk, 2014). If more and more public buildings nowadays already have their BIM digital models, is it possible to take over these models and effectively repurpose them into virtual environments applicable in virtual reality where for example fire drills could be realized without the need to use the premises of real buildings? In practice, this article concerns the conversion of a 3D architectural building model in the IFC data format (a standard data format for BIM) from BIM/CAD software Autodesk Revit to game engine Unity, its subsequent modification, and creation of an environment as faithful to its real-life counterpart as possible. The created virtual environment can then be used to manage experiments, spatial analyses, and case studies. The process described in this article included the following steps: Conversion of the selected building model to a data format supported by Unity and its import to said software. Rearrangement of a complex and often nonuniform hierarchy of imported building elements and elimination of objects with far too detailed geometry or redundant objects that would not be accessible by the user in the final version of the model. Fixing basic construction elements that did not correspond with their real form or were needlessly fragmented into several separate objects. Editing out geometric and topological errors produced by the conversion process. Selection of relevant objects that were to be included in the environment. Modeling the interior (furnishing, plants, signs, doors, etc.) and exterior of the building based on their real counterparts so that the virtual objects look as similar as possible to the real ones. And the lighting of the scene along with the final adjustment of some objects geometry where needed. The final virtual environment was then utilized in an application build intended for use in virtual reality and was part of a study dealing with the comparability of experiments in real and virtual environments with a focus on wayfinding and locomotion where an emergency evacuation took place in both the real and virtual environments of the building and chosen parameters were then measured and evaluated. Potential possibilities regarding optimization and limits of the current presented solution are discussed as well. [ABSTRACT FROM AUTHOR]

The spatial conflicts in the construction of high-speed railways not only reduce project efficiency, but also lead to serious accidents. To address these key issues, this paper presents a dynamic simulation method for constructions processes based on a virtual geographic environment. This approach can facilitate the identification of conflicts in the construction scheme through accurately expressing and analysing the intricate spatio-temporal relations among railway facility components, construction equipment and the surrounding environment. First, a high-precision virtual geographic scene in which the construction process and methods can be visualized and modelled intuitively is established with terrain, imagery, and engineering 3D models. Then, the overall construction processes can be accurately simulated by a sequential display of the railway components and the behaviour of construction equipment. To simulate the behaviour of construction equipment, the linkage relations between each joint of construction machinery are accurately modelled and animation control parameters are extracted. Finally, a construction simulation of a high-speed railway bridge was performed, and the experimental results show that the proposed method can provide a scientific basis for the optimization of complex engineering construction schemes, safety hazard assessments, and related full life cycle tasks. [ABSTRACT FROM AUTHOR]